bonwill



'(No Model.) 2 SheetsSheet 1.

W. G. A. BONWILL.

DENTAL ENGINE.

No. 372,397. Patented Nov. 1, 1887.

WITNESSES:

(No Model.) 2 Sheets-Sheet 2. .W. G. A. BONWILL.

DENTAL ENGINE.

Patented N v. 1, 1887.

fill i ENTOR :5???" m. Z v/M v I N. PETERS. Pholo-Lilhngraphor, wamin mn, D; c.

UNrrn TATES ATENT rrrcn.

WILLIAM G. A. BONIVILL, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO TIIE S. S. \VHITE DENTAL MANUFACTURING COMPANY, OF SAME PLACE.

DENTAL ENGINE.

SPECIFICATION forming part of Letters Patent No. 372,397, dated November 1, 1887.

Application tiledDccembcr 21, 1886. Serial No. 222,907. (No model.)

To all. whom it may concern:

Be it known that I, WILLIAM G. A. Bon- WILL, a citizen of the United States, residing at Philadelphia,inthe county ofPhiladelphia and State of Pennsylvania, have invented certain new and useful Improvements in Dental Engines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it apperlains to make and use the same.

My invention relates more especially to engines of that class which rotate an operatingtool for the performance of dental and surgical operations. In this class of engines, wherein it is a necessity that the handpiece which carries the operating-tool shallbe capable of being moved freely about in the performance of delicate operations, the tool should be rotated or driven with certainty and regularity, and it has been my experience that a drivingbelt is the best means for attaining this end. I therefore show such an engine in illustrating my invention.

The object of my present invention is to improve the engine in respect to its lateral arm and its capability of adjustment relatively to the upright standard.

I will describe my said improvements, in connection with the accompanying drawings, as organized in the best way now known to me, and will then particularly point out the subjectmatter claimed by me herein in asummary at the close of this specification.

In said drawings, Figure 1 is a View in side elevation of my improved engine. Fig. 2 is a view, on a larger scale than that of Fig. 1, of the butt-end of the hand-piece and the joint and belt connections thereof, by which said hand-piece is connected to a rocking arm of the engine. Fig. 3 is a rear view of the parts shown in Fig. 2, looking in the direction of the arrow 3 in Fig. 2. Fig. t is an enlarged sectional view of a portion of one of the belt pulleys, showing a supplemental or auxiliary groove, by which to secure a more thorough bite or hold on the driving-cord than is permitted by the usual groove of a drivingcord pulley. Fig. 5 is a similar view, with the main and supplemental grooves differing slightly from those of Fig. 4. Fig. 6 is an edge view of the main driving-pulley and parts lying immediately adjacent thereto. Fig. 7 is a view of the engine-head and lateral enginearm, the latterbeing adjusted to a vertical po 55 sition, so as to be out of the way and form virtually a prolongation of the upright enginestandard when the engine is not in use. Fig. Sis a similar view at right angles to that of Fig. 7, and with the greater portion of the lat- 50 eral engine-arm in section. Fig. 9 shows a modification of the clamp-screw forming part of the supporting devices of the lateral arm; and Fig. 10 is a view in side elevation of the forearm of the engine, and with the front 5 or outer end of the lateral engine arm in section, to show more particularly the swiveling detachable connection between the two arms.

The base A, pedestal B, main driving-pulley O, pitmau D, treadle E, and upright en- 7c gine arm or standard F are of the usual construction, with the exception that a pinionwheel G is attached to the axle of the main driving-pulley O, or forms part of said pulley, whereby the said driving-pulley 0 may be more rapidly and powerfully driven when 0ceasion rcquires-as in surgical operations, in sawing through thick bones, for instance-by means of agear-wheeLH, on one end of a crankshaft, II, fitted to be turned by a handle, H It is a fact that by this gear-connection a more rapid and powerful action can be had than by the foot-treadle.

Inadditiou to the usual concave or tapered groove, c,in the driving-pulley, Iprefer to employ a supplemental groove, 0, so as to afford a firm grasp or bite on the driving cord or band. (See Figs. 4t and 5.)

Au engiuehead, I, is fitted upon the upper end of the upright engine-arm F, preferably by means of a turning or swiveling pintle or connection, 1', so that the said engine-head and parts carried thereby may have a horizontal adjustment or swinging movement upon said engine-arm, as usual. Two pulleys, J J, are mounted upon said engine-head near its upper end, and the axes of these pulleys are coincident. The lateral arm K of the engine is jointed by an offset-joint, 70, to the enginehead, and carries at its outer end two pulleys, L L, while the front end of said lateral arm K, by an offset-joint, m, is jointed to the forearm IOO M of the engine, and the lower end of said forearm is likewise jointed by a joint, 41, to the hand-piece bracket-frame N,which carries two sets of pulleys, O O P P, on opposite sides of said frame, the said joint n being offsetfrom the axes of said pulleys. An endless driving cord or band, Q, passes from the main drivingpulley 0 around the pulleys J J L L, to or between the pulleys O O P P ,and around the pulley R, fixed on the butt-end of the rotating tool-carrying spindle S of the hand-piece, said spindle S rotating in bearings in the handpiece casing T, and is steadily driven bysaid enless driving cord or belt.

By means of the arrangement of the beltpulleys and offset-joints, which are substantially the same as that shown in my patent of July 3l, 1883, the tension ofthe belt is regulated and maintained substantially equal in what ever position thehand-piece and operating-tool driven thereby may be during the operation of the engine. I have, however, changed the organization of the joint and pulleys of the hand-piece bracket-frame, which is fitted to swivel or turn freely on the rear end of the tooldriving spindle S, in thatI place the offset-joi nt intermediate between the pulleys O and P, the axes of which are coincident, and the pulleys O P, the axes of which are also coincident, whereby the hand-piece, by means of its bracket-frame N, may be moved or rocked upon the lower end of the forearm M to either side of its longitudinal line, corresponding to the capability of the human hand at the wrist, the pulleys on the bracket-frame N thereby fitting the hand-piece for a wider range of movement than in my aforesaid patent, and at the same time compensating adriving cord or belt to preserve its proper tension in operating the engine. y

In order to permit greater freedom of movement between the outer end of the lateral engine-arm K and the upper end of the forearm M, I make a swiveling connection between the two, consisting of an annularly-grooved spindle, 7c, fitti ng the front tubular end ofsaid lateral arm K, and split said tubular end of the said arm, and provide one or moremembers thereof with projections or teats k",wliicl1 spring into the annulargroove ofthe spindlelt,so as to lock the two together and permit of ready separation, and at the same time permit afree swiveling movement of the forearm M upon the arm K. A similar joint is employed between the lower end of the forearm M and spindle n of the hand-piece bracket-frame N, as shown in- Fig. 10.

In my aforesaid patent of July 31, 1883, I maintain the lateral engine-arm in a normal lat eral position substantially at right angles to the upright engine-arm, (marked in this case F,) by means of a spiral spring and sliding bracketarm but in that case the connection is such that the upward movement of the lateral arm is limited. I have improved that construction by inclosing the spiral spring and sliding connection in the slotted tubular lateral engine-arm K and connecting a sliding block. U, acted on by said spring, to the engine-head by means of a pitman, V, whereby not only can the arm be maintained in a substantially lateral position relatively to the upright arm of the engine, but said lateral arm may be rocked vertically upward, in order to carry it out of the way of the operator when the engine is not in use, and maintain it in that position by the action of said spring-connection, the forearm and other parts carried thereby hanging vertically downward, parallel, or substantially parallel, with said lateral arm thus adjusted to a perpendicular position. I be lieve my engine is the first one in which the lateral arm could be adjusted and maintained vertically as a prolongation of the upright arm of the engine, so as to be out of the way of the operator. The tension of the sustaining-spring of the lateral arm can be regulated by the sliding block U and setnut u.

I claim as my invention- The combination of the upright engine arm with the lateral engine-arm by means of a joint, an inclosed sustaining-spring, and a pitman-connection,whereby-said engine-arm may be supported-in a normally-lateral position, or be moved upvertically out of the Way, substantially as described.

In testimony whereof I'affix my signature in presence of two witnesses.

WM. G. A. BONWILL.

Witnesses:

ELI T. STARR, J as. 'F. LYND. 

